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The aim of this study is focused on the elaboration of new bio-based alumina concentrated suspensions with rheological properties adapted to the tape casting process and with low environmental impact. Natural polymers extracted from plants were identified as promising candidates in order to substitute the classical organic additives. The aqueous suspensions were prepared from bio-polymer additives. The interactions between different organic additives with alumina were characterized by zeta-potential and quartz crystal microbalance measurements. The influence of the incorporation order of the different organic additives on the viscosity of the suspension was evaluated. Then, mechanical properties of the green and sintered tapes were determined in relation with the nature of bio-polymer additives. [ABSTRACT FROM AUTHOR]

In this paper, the effects of lithium chloride (LiCl) on 1-allyl-3-methylimidazolium chloride (AMIMCl) and cellulose/AMIMCl were studied by steady-state and dynamic rheology experiments. After adding LiCl, a suprastructure may be formed in AMIMCl/LiCl because of fiber drawing and shear-thinning behavior. Moreover, the size of cellulose coil swelled by adding LiCl. In the master curve of cellulose-AMIMCl/LiCl solution, the critical overlap concentration was c = 0.63 and the entangled concentration was c = 2.27 for the entangled regime. Dependence of η on cellulose concentration in cellulose-AMIMCl/LiCl was η ∼ c and c in dilute and semi-dilute untangled regimes, respectively. Therefore, the AMIMCl/LiCl mixture was not a θ solvent for the neutral polymer. The solubility of cellulose decreased and degradation was aggravated after adding LiCl. [ABSTRACT FROM AUTHOR]

This work includes the study of the hydrolytic biodegradation of coatings based on polylactic acid, polyglycolic acid and hydroxyapatite. These coatings were obtained by cathodic electrodeposition over piezoelectric quartz crystals, using an electrolyte with different polymer/ceramic ratios but with a fixed time, voltage and volume of solvent. The films obtained were immersed into a simulated body fluid (SBF) during 1, 3, 5, 7 and 10 days at constant temperature and pH. The coatings were analyzed by EIS and QCM to find a correlation between frequency changes and the total transferred mass. [ABSTRACT FROM AUTHOR]